1. Field of Invention
The present invention relates to a light emitting diode (LED). More particularly, the present invention relates to a LED having a lens with a patterned surface.
2. Description of Related Art
A LED is a kind of junction diode mainly composed of p type and n type epitaxy layer on the semiconductor substrate. After forming the epitaxy structure, the chip is sliced and then fixed on a panel. Then, the chip is wired and packaged to form the LED. Generally speaking, the material for packaging of the LED is epoxy, polycarbonate (PC), or other polymer that is highly pervious to light. By the transition property of the semiconductor carrier, it emits light corresponding to the wavelength of the energy gap of the material or the energy level of quantum well. Thus forms the light of the LED. Therefore, by adjusting the structure of the material, the LED will emit light of different colors by different current.
The LED is a kind of light source that conserves energy. Although conventional light sources, such as light bulbs, are inexpensive, there are disadvantages, such as low efficiency, high power consumption, short lifespan, and fragility. Fluorescent lamps are less power consuming, but they are fragile and the waste contains mercury that pollutes the environment. The LED has long lifespan, low power consumption, and no mercury. Thus makes the LED an ideal light source. Besides, the LED has a variety of types and applications. Hence, it has already become an essential tool in the modern world.
Reference is made to FIG. 1 which is a schematic diagram of a conventional LED. In FIG. 1, a LED 100 includes a package 110, a light-emitting diode chip 120 and a lens 130. The light-emitting diode chip 120 is mounted on the package 110. The lens 130 is mounted on the package 110 and envelops the light-emitting diode chip 120. Typically, the lens 130 is smooth and curved. Therefore, parts of light 150 produced by the light-emitting diode chip 120 may be reflected to the back of the LED 100 by the lens 130.
The parts of light 150 are unable to light the front of the LED 100 due to the reflection of the lens 130. This will cause the LED 100 has bad light efficiency. That is, a conventional LED has to waste some power on producing the parts of light unable to light the front of the LED. Therefore, the LED is still incapable of being applied to many technique fields, which needs high brightness light sources, at the present day.